Electric crucible



Patented Jan. 2, 1951 UNITED STATES PATENT OFFICE ELECTRIC CRUCIBLEFernand Salvador, Marseille, France Application August 30, 1948, SerialNo. 46,842 In France September 12, 1947 (Cl. 13u- 21) 1 Claim. l

The present invention has for object an electric Crucible for rapidlyreaching temperatures of 900 C. and above, and particularly for meltingsoft metals and other materials.

To obtain this result, the Crucible according to the inventionconcentrates the maximum of calories at the interior of the Crucible,that is to say on the material to be treated, by disposing the heatingelements at the interior, that is to say in direct Contact with the saidmaterial. These heating elements, ofappropriate number, are disposedalong interior generatrices of the lateral cylindrical wall of theCrucible in projecting portions of the wall which penetrate into thematerial to be treated, thus assuring a maximum heat-exchange surface.

The invention is shown by way of example in the accompanying drawing,wherein:

Fig. 1 shows a central vertical section.

Fig. 2 shows a plan view.

To obtain a thermal conductivity which is great as possible, the heatingelements, which are long and of cylindrical or like form, are lodged ininterior projections 2 of the lateral wall 5 of a Crucible l having abase 3, these projections being hollowed axially from top to bottom toform cavities 4 for the heating elements (not shown). Thus the Casing ofeach heating element can lit snugly to the wall of the Crucible. Thehollowed cavities 4 are readily accessible through the lower part of theCrucible.

Each heating element is formed of a tube of refractory material whichcontains resistances oi high resistivity. All the heating elements arereadily interchangeable, being slidable in their cavities 4. In order toprotect the resistances against oxidisation they are embedded in magnesia which prevents any Contact with the air.

All the resistances or heatingr elements are retained in aquasi-vertical position by appropriate means, and are suitably Connectedup electrically.

The Crucible is surrounded with heat insulation (not shown) which is inturn protected by an exterior casing, (not shown).

The Crucible is provided with two diametrically opposed journals 6integral with the wall of the Crucible, for pivoting purposes.

A channel 1, which is placed externally along a generatrix, connects ahole 8 pierced at or near the base of the Crucible to a pouring spout 9in 2 order that only that part of the material which is free fromfloating impurities is poured out.

To prevent inclusion of the floating impurities when pouring out, ahorizontal membrane I0 is provided.

I Claim:

Electric Crucible for heating materials so as to rapidly attaintemperatures of 900 C. and above, having a Cylindrical wall, inwardlyprojecting portions disposed along generatrices of said wall topenetrate into the material to be treated and thereby increase thesurface of radiation and heat exchange towards the interior of the saidCrucible, each said projecting portion being hollowed axially from topto bottom to provide a Cavity therein, and a heating element ofcorresponding shape arranged in each said cavity, a pouring spout on theoutside of the upper part of the crucible integral with a verticalChannel external of the wall, a hole pierced in said wall near its basein Communication with said channel whereby only treated material fromthe lower part of the Crucible and therefore free from all floatingimpurity can be poured from said spout, and a horizontal membrane at theupper part of the Crucible to prevent passage of floating impuritiestowards the spout when the Crucible is tilted to pour out the treatedmaterial.

FERNAND SALVADOR.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 15,378 Weidenthal June 6,1922 839,343 Vogel Dec. 25, 1906 1,032,647 Bell July 16, 1912 1,418,030Speirs May 30, 1922 1,508,490 Wiechert et al Sept. 16, 1924 1,713,249Abbott et al May 14, 1929 2,190,135 Morgan et al Feb. 13, 1940 2,237,110Osterheld Apr. 1, 1941 2,368,173 Tama Jan. 30, 1945 FOREIGN PATENTSNumber Country Date 415,895 Great Britain Sept. 6, 1934

